Prevalence and causes of low vision and blindness in a Chinese population with type 2 diabetes: the Dongguan Eye Study

To assess the prevalence and causes of low vision and blindness in type 2 diabetes patients, a population-based cross-sectional study including 8952 rural-dwelling residents aged 40 years or older from Hengli Town in Southern China was conducted. Participants underwent standard interviews, physical measurements, laboratory tests, and comprehensive eye examinations. Low vision and blindness were defined based on WHO criteria. Visual acuity data were available for 1348 (89.9%) of the 1500 subjects with type 2 diabetes. Age-standardized prevalence of bilateral low vision and blindness assessed in the better-seeing eye was 2.9% (95% confidence interval [CI]: 2.0–3.8) and 0.7% (95% CI: 0.2–1.1) based on best-corrected visual acuity (BCVA). Cataracts were the primary cause of low vision and blindness. Visual impairment was associated with age (odds ratio [OR]: 3.73, 95% CI: 2.39–5.83), education level (OR: 3.21, 95% CI: 1.63–6.29), duration of diabetes (OR: 1.14, 95% CI: 1.04–1.25) and body mass index (OR: 0.86, 95% CI: 0.77–0.95). Our data suggest that approximately 70% of visual impairment in this diabetic population could be eliminated with appropriate cataract surgery or spectacle correction. Greater consideration should be given to older type 2 diabetes patients with a level of lower education.